This research adopted Robust Decision Making framework to re-evaluate four alternative strategies proposed by Comprehensive Flood Management Plan in Yeong San River basin (MLTM, 2005) considering uncertainties of future floods under condition of climate change. To reflect the uncertainties, multiple sets of future flood scenarios were used with three uncertainty factors: change in rainfall intensity based on climate change scenarios (RCP), change in temporal and spatial distribution. With combinations of these factors, 216 plausible flood scenario sets were generated and the performance of the four alternatives under different future states were evaluated. From the results, the most robust alternative among the strategies was identified. Moreover, the main factor which triggers strategies’ poor performance was discovered through assessment of the uncertainty factors. These information can provide detailed insights to decision makers and can be utilized to overcome alternatives' potential vulnerabilities by modifying the strategy to be more robust.